Trolling plate



Sept- 1941 G. A. w. EHMKE 2,256,898

TROLLING PLATE Filed April 10, 1939 61/57/474. VKf/f/M/rz' INVENTOR BY W ATTORNEY Patented Sept. 23, 1941 UNITED STATES PATENT QFFI'CE 2,256,898 I r f I TROLLING PLATE Gustav A. W. Ehmke, Spokane, Wash. Application April 10, 1939, Serial No. 267,046

7 3 Claims.

My present invention relates to improvements in trolling plates with special reference to that class used in connection with outboard motors for the propulsion of small fishing boats. It being well known that motors so used, even when throttled down to their slowest idling speed, propel the boat too fast for trolling for game fish.

The invention resides in a brace, or bracket preferably attached to, and depending from the anti-cavitation plate on the motor immediately above the propeller, in any suitable manner, depending on the construction of the motor. The shank of the brace or bracket depending down- Wardand having lugs orears laterallydisposed, to which are hingedly attached the two halves of the trolling plate, held in normal position transversely of a longitudinal line throughthe boat, the said halves of the plate being directly in the rear of the propeller and normally parallel therewith, being maintained in that position by a spring, preferably of the coiled type, and the hinged connections to the brace. This position is also the trolling position.-

When the motor is operating at high speed, the halves of the trolling plate open along a vertical line through the center, each half assuming a position with its inner, vertical edge cutting the water vertically, and the halves being thus parallel, form a double rudder and are maintained in this position by the force of the water on their faces, during which time the said spring is in tension, ready to return the said halves to their normal position upon accelerat ing the speed of the motor: The action of the trolling plate is entirely automatic, and responsive only to the speed of the motor and propeller, and being actuated by the amount of the force of the water from the latter as it impinges upon the face of the trolling plate.

Objects The primary object of my invention is to provide a device that will reduce the speed of the boat from approximately four miles per hour, which, in many cases, is the slowest-speed possible with a motor throttled down to idling speed,

to a suitable trolling speed of approximately one when the latter has been' throttled down to its lowest idling speed.

D in

In the accompanying drawingwhich is a part in, and I therefore consider and claim'as my own,

all such modifications and adaptations of the form of the device as fairly fall within the scope of the appended claims.

Referring to the drawing, in which'the several parts are shown and designated by. numerals, the same numeral being used to designate the same part throughout the several views, and in which Fig. 1 is a side elevation ofa fragmental portion of the rear of a boat having an outboard motor attached at the rear, and one embodiment of my invention attached to the anti-cavitation plateof said motor, wherein the trolling plate isin normal, or trolling position. 1

Fig. 2 is a rear elevation of the device as attached to the anti-cavitation plate, as projected from Fig. 1.

Fig. 3 is similar to Fig. 1 except that the trolling plate is shown open, or the halves have been swung around parallel to each other, as when the motor and propeller are rotating at full speed.

Fig. 4 is an enlarged view, in perspective, of the preferred form of my invention with the right hand half of the trolling plate shown open.

Fig. 5 is an enlarged transverse section of the assembled device taken on line 55 of Fig. 1.

Fig. 6 is also an enlarged transverse section through the depending brace, taken on line 66 of Fig. 1.

Figs. '7, 8, and 9 are enlarged views of a modilied form of my invention, in which,

Fig. 7 is a side elevation showing the halves of the trolling plate hinged at their vertical center, with the spring vertically disposed.

Fig. 8 is a transverse section on line 38 of Fig. 7.

Fig. 9 is a similar view through the brace only, and taken on line 9-9 of Fig. '7.

Description and operation The preferred embodiment consists of a depending brace, or shank I having hinge plates 2 integral therewith, and attaching means as 3 for attachment to the anti-cavitation plate A of the motor. Hingedly attached to said plates 2 are the hinge ears 4 and 5 of each half of 6 and I of the trolling plate, respectively; in the rear of each of said plate halves 6 and I and about midway between the hinge ears is attached the ends of a preferably coiled spring l2, disposed horizontally between the hinge pins 8 and the plate halves to maintain their faces in alignment as shown best in Fig. 5. The straight edges of the plate halves 6 and I are bevelled as at 9 to offer The hinge plates 2 are provided at their outer extremities with projections l0, Fig. 6, to maintain the plate halves 6 and I in vertical, parallel relation to each other when open, as in the dotted lines in Fig. 5, it being understood that both plate halves 6 and 1 open simultaneously, but in opposite directions, and around separate hinge pins 8, the brace I being provided with a widened nose II 'to prevent kinking or distorting the middle coils of the spring l2.

--In order to prevent the plate halves 6 and 1 from becoming out of line with their faces. a projection I3 is provided on each hinge plate 2 so that the bevels on these co-act with the correspondingly bevelled edges of the straight edges on the hinged plate halves. All front edges of the deviceare streamlined, to offer the least resistance to the Water when the plate halves are in open position.

The embodiment shown in Figs. 7, 8, and 9 is different from the aboveonly in the action of the spring and the number of hinges; the spring being vertically disposed around the single hinge pin, and subject to a torsional strain instead of the tensional strain of the embodiment shown in Figs. 1 to 6 inclusive.

The upper portion of the brace may be attached to the motor in any suitable manner, or as shown in Fig. 1 in full, or in the dotted lines by clamping to the dependingtubes of the motor.

From the foregoing, the construction and operspring connecting each of the halves of the trolling plate.

2. A fiat bifurcated trolling plate mechanism for usein combination with an outboard motor for boats, having a supporting arm adapted for attachment to the outboard motor structure, hinge members on the arm, a flat trolling plate in halves, hinge members on each half for connection to the hinge members on the'arm, a spring, the ends of which are attached to the halves of the plateto flexibly hold them in alignment across their front faces when not acted upon by a displacing force of by the motor. a

'3. A trolling plate mechanism of three-major pieces consisting of an arm for attachment to a suitable place 'on'a motor'-propeller frame, a

flat trolling plate inhalves, and a spring, connecting said halves, said halves of the trolling plate being hingedly'connected to said arm in such manner as to be of service as a trolling plate at reduced speed of the motor, or as a double and parallel rudder when the speed of the motor is in-' creased, a spring attached at its ends to each of:

water from a propeller driven' 

